The comma ( , ) is a punctuation mark dat appears in severaw variants in different wanguages. It has de same shape as an apostrophe ( ' ) or singwe cwosing qwotation mark in many typefaces, but it differs from dem in being pwaced on de basewine of de text. Some typefaces render it as a smaww wine, swightwy curved or straight but incwined from de verticaw, or wif de appearance of a smaww, fiwwed-in figure 9.

The comma is used in many contexts and wanguages, mainwy for separating parts of a sentence such as cwauses, and items in wists, particuwarwy when dere are dree or more items wisted. The word comma comes from de Greekκόμμα (kómma), which originawwy meant a cut-off piece; specificawwy, in grammar, a short cwause.[1][2]

There are awso a number of comma-wike diacritics wif "COMMA" in deir Unicode names. These do not serve a punctuation function, uh-hah-hah-hah. A comma-wike wow qwotation mark is awso avaiwabwe (shown bewow; raised singwe qwotation marks are not shown).

In de 3rd century BC, Aristophanes of Byzantium invented a system of singwe dots (distinctiones) dat separated verses (cowometry) and indicated de amount of breaf needed to compwete each fragment of de text when reading awoud.[3] The different wengds were signified by a dot at de bottom, middwe, or top of de wine. For a short passage (a komma), a media distinctio dot was pwaced mid-wevew ( · ). This is de origin of de concept of a comma, awdough de name came to be used for de mark itsewf instead of de cwause it separated.

The mark used today is descended from a diagonaw swash, or virguwa suspensiva ( / ), used from de 13f to 17f centuries to represent a pause. The modern comma was first used by Awdus Manutius.[4][5]

Moreover, de mark is used to spearate words, phrases and cwauses in a sentence to hewp it to be understood- to divide a sentence into easiwy assimiwated bite-sized pieces. However, dere are many oder functions of de comma, such as "setting of qwestions", "emphisizing point of view" and etc.[6]

In generaw, de comma shows dat de words immediatewy before de comma are wess cwosewy or excwusivewy winked grammaticawwy to dose immediatewy after de comma dan dey might be oderwise. The comma performs a number of functions in Engwish writing. It is used in generawwy simiwar ways in oder wanguages, particuwarwy European ones, awdough de ruwes on comma usage – and deir rigidity – vary from wanguage to wanguage.

Commas are pwaced between items in wists, as in They own a cat, a dog, two rabbits, and seven mice. Some Engwish stywe guides recommend dat a comma be used before de finaw conjunction (and, or, nor) in a wist of more dan two ewements. A comma used in such a position is variouswy cawwed a seriaw comma, an Oxford comma, or a Harvard comma (after de Oxford University Press and Harvard University Press, bof prominent advocates of dis stywe). Such use of a comma sometimes prevents ambiguity:

The sentence I spoke to de boys, Sam and Tom couwd mean eider I spoke to de boys and Sam and Tom (I spoke to more dan dree peopwe) or I spoke to de boys, who are Sam and Tom (I spoke to two peopwe);

I spoke to de boys, Sam, and Tom – must be de boys and Sam and Tom (I spoke to more dan dree peopwe).

The seriaw comma does not ewiminate aww confusion, uh-hah-hah-hah. Consider de fowwowing sentence:

I dank my moder, Anne Smif, and Thomas. This couwd mean eider my moder and Anne Smif and Thomas (dree peopwe) or my moder, who is Anne Smif; and Thomas (two peopwe). This sentence might be recast as "my moder (Anne Smif) and Thomas" for cwarity.

I dank my moder, Anne Smif and Thomas. Because de comma after "moder" is conventionawwy used to prepare de reader for an apposite phrase – dat is, a renaming of or furder information about a noun – dis construction suggests dat my moder's name is "Anne Smif and Thomas". Compare "I dank my friend, Smif and Wesson", in which de ambiguity is obvious.

As a ruwe of dumb, The Guardian Stywe Guide[7]
suggests dat straightforward wists (he ate ham, eggs and chips) do not need a comma before de finaw "and", but sometimes it can hewp de reader (he ate cereaw, kippers, bacon, eggs, toast and marmawade, and tea). The Chicago Manuaw of Stywe, and oder academic writing guides, reqwire de seriaw comma: aww wists must have a comma before de "and" prefacing de wast item in a series.

If de individuaw items of a wist are wong, compwex, affixed wif description, or demsewves contain commas, semicowons may be preferred as separators, and de wist may be introduced wif a cowon.

In news headwines, a comma might repwace de word "and", even if dere are onwy two items, in order to save space, as in dis headwine from Reuters:[8]

Commas are often used to separate cwauses. In Engwish, a comma is used to separate a dependent cwause from de independent cwause if de dependent cwause comes first: After I fed de cat, I brushed my cwodes. (Compare dis wif I brushed my cwodes after I fed de cat.) A rewative cwause takes commas if it is non-restrictive, as in I cut down aww de trees, which were over six feet taww. (Widout de comma, dis wouwd mean dat onwy de trees more dan six feet taww were cut down, uh-hah-hah-hah.) Some stywe guides prescribe dat two independent cwauses joined by a coordinating conjunction (for, and, nor, but, or, yet, so) must be separated by a comma pwaced before de conjunction, uh-hah-hah-hah.[9][10] In de fowwowing sentences, where de second cwause is independent (because it can stand awone as a sentence), de comma is considered by dose guides to be necessary:

Mary wawked to de party, but she was unabwe to wawk home.

Designer cwodes are siwwy, and I can't afford dem anyway.

Don't push dat button, or twewve tons of high expwosives wiww go off right under our feet!

In de fowwowing sentences, where de second hawf of de sentence is not an independent cwause (because it does not contain an expwicit subject), dose guides prescribe dat de comma be omitted:

Mary wawked to de party but was unabwe to wawk home.

I dink designer cwodes are siwwy and can't afford dem anyway.

However, such guides permit de comma to be omitted if de second independent cwause is very short, typicawwy when de second independent cwause is an imperative,[9][10] as in:

Sit down and shut up.

The above guidance is not universawwy accepted or appwied. Long coordinating cwauses are nonedewess usuawwy separated by commas:[11]

She had very wittwe to wive on, but she wouwd never have dreamed of taking what was not hers.

In some wanguages, such as German and Powish, stricter ruwes appwy on comma usage between cwauses, wif dependent cwauses awways being set off wif commas, and commas being generawwy proscribed before certain coordinating conjunctions.

The joining of two independent sentences wif a comma and no conjunction (as in "It is nearwy hawf past five, we cannot reach town before dark.") is known as a comma spwice and is sometimes considered an error in Engwish;[12] in most cases a semicowon shouwd be used instead. A comma spwice shouwd not be confused, dough, wif asyndeton, a witerary device used for a specific effect in which coordinating conjunctions are purposewy omitted.

Commas are awways used to set off certain adverbs at de beginning of a sentence, incwuding however, in fact, derefore, neverdewess, moreover, furdermore, and stiww.

Therefore, a comma wouwd be appropriate in dis sentence.

Neverdewess, I wiww not use one.

If dese adverbs appear in de middwe of a sentence, dey are fowwowed and preceded by a comma. As in de second of de two exampwes bewow, if de two sentences are separated by a semicowon and de second sentence starts wif an adverb, dis adverb is preceded by a semicowon and fowwowed by a comma.

Commas are often used to encwose parendeticaw words and phrases widin a sentence (i.e., information dat is not essentiaw to de meaning of de sentence). Such phrases are bof preceded and fowwowed by a comma, unwess dat wouwd resuwt in a doubwing of punctuation marks or de parendeticaw is at de start or end of de sentence. The fowwowing are exampwes of types of parendeticaw phrases:

Introductory phrase: Once upon a time, my fader ate a muffin, uh-hah-hah-hah.[13]

A comma is used to separate coordinate adjectives (i.e., adjectives dat directwy and eqwawwy modify de fowwowing noun). Adjectives are considered coordinate if de meaning wouwd be de same if deir order were reversed or if and were pwaced between dem. For exampwe:

Some writers precede qwoted materiaw dat is de grammaticaw object of an active verb of speaking or writing wif a comma, as in Mr. Kershner says, "You shouwd know how to use a comma." Quotations dat fowwow and support an assertion are often preceded by a cowon rader dan a comma.

Oder writers do not put a comma before qwotations unwess one wouwd occur anyway. Thus dey wouwd write Mr. Kershner says "You shouwd know how to use a comma."

When a date is written as a monf fowwowed by a day fowwowed by a year, a comma separates de day from de year: December 19, 1941. This stywe is common in American Engwish. The comma is used to avoid confusing consecutive numbers: December 19 1941.
Most stywe manuaws, incwuding The Chicago Manuaw of Stywe[14]
and de AP Stywebook,[15]
awso recommend dat de year be treated as a parendeticaw, reqwiring a second comma after it: "Feb. 14, 1987, was de target date."

If just monf and year are given, no commas are used:[16] "Her daughter Apriw may return in June 2009 for de reunion, uh-hah-hah-hah."

Commas are used to separate parts of geographicaw references, such as city and state (Dawwas, Texas) or city and country (Kampawa, Uganda). Additionawwy, most stywe manuaws, incwuding The Chicago Manuaw of Stywe[17]
and de AP Stywebook,[18]
recommend dat de second ewement be treated as a parendeticaw, reqwiring a second comma after: "The pwane wanded in Kampawa, Uganda, dat evening."[19]

In representing warge numbers, from de right side to de weft, Engwish texts usuawwy use commas to separate each group of dree digits in front of de decimaw. This is awmost awways done for numbers of six or more digits and often for five or four digits but not in front of de number itsewf. However, in much of Europe, Soudern Africa and Latin America, periods or spaces are used instead; de comma is used as a decimaw separator, eqwivawent to de use in Engwish of de decimaw point. In India, de groups are two digits, except for de rightmost group. In some stywes, de comma may not be used for dis purpose at aww (e.g. in de SI writing stywe[22]); a space may be used to separate groups of dree digits instead.

Commas are used when rewriting names to present de surname first, generawwy in instances of awphabetization by surname: Smif, John, uh-hah-hah-hah. They are awso used before many titwes dat fowwow a name: John Smif, Ph.D.

In his 1785 essay An Essay on Punctuation, Joseph Robertson advocated a comma between de subject and predicate of wong sentences for cwarity; however, dis usage is regarded as an error in modern times.

The good taste of de present age, has not awwowed us to negwect de cuwtivation of de Engwish wanguage.

There is awso some difference regarding de use of de seriaw comma, which is an optionaw comma pwaced before de coordinating conjunction in a wist of dree or more items:

They served appwes, peaches, and bananas. (seriaw comma used)

We cweaned up cores, pits and skins. (seriaw comma omitted)

The seriaw comma is awso known as de Oxford comma, Harvard comma, or series comma. It is sometimes perceived as overwy carefuw or an Americanism[citation needed], but its usage occurs widin bof American and British Engwish. It is cawwed de Oxford comma because of its wong history of use by Oxford University Press.[27]

Opinions among writers and editors differ on wheder to use de seriaw comma. A majority of American stywe guides mandate use of de seriaw comma, incwuding The Chicago Manuaw of Stywe, Strunk and White's The Ewements of Stywe, and de U.S. Government Printing Office Stywe Manuaw. The AP Stywebook for journawistic writing advises against it. It is used wess often in British Engwish, but some British stywe guides reqwire it, incwuding de Oxford University Press stywe manuaw and Fowwer's Modern Engwish Usage. Some writers of British Engwish use it onwy where necessary to avoid ambiguity.

According to New Hart's Ruwes, "house stywe wiww dictate" wheder to use de seriaw comma, and "The generaw ruwe is dat one stywe or de oder shouwd be used consistentwy." No association wif region or diawect is suggested, oder dan dat its use has been strongwy advocated by Oxford University Press.[28]

Barbara Chiwd advises dat "it is a good idea to put a comma before de wast item in a series", but cwaims dat in de United States dere is a trend toward a decreased use of de comma generawwy.[29] This is reinforced by an articwe by Robert J. Samuewson in Newsweek.[30]Lynne Truss says dat generaw decwine in usage of commas is eqwawwy true in de UK, where it has been a swow, steady trend for at weast a century:

During de Second Worwd War, de British carried de comma over into abbreviations. Specificawwy, "Speciaw Operations, Executive" was written "S.O.,E.". Nowadays, even de fuww stops are freqwentwy discarded.[31]

Punctuation has been added to many wanguages which originawwy devewoped widout it, incwuding a number of different comma forms. European wanguages wike German, French, Itawian, Spanish, and Portuguese use de same comma as Engwish wif simiwar spacing, dough usage may be somewhat different. For instance, in Standard German, subordinate cwauses are awways preceded by commas.

Modern Greek uses de same Unicode comma for its kómma (κόμμα)[32] and it is officiawwy romanized as a Latin comma,[33] but it has additionaw rowes owing to its confwation wif de former hypodiastowe, a curved interpunct used to disambiguate certain homonyms. The comma derefore functions as a siwent wetter in a handfuw of Greek words, principawwy distinguishing ό,τι (ó,ti, "whatever") from ότι (óti, "dat").[32]

The enumeration or ideographic comma—U+3001、IDEOGRAPHIC COMMA—is used in Chinese, Japanese punctuation, and somewhat in Korean punctuation, uh-hah-hah-hah. In de Peopwe's Repubwic of China and in Norf/Souf Korea, dis comma (t頓號, s顿号, pdùnhào) is usuawwy used onwy to separate items in wists, whiwe in Japan it is de more common form of comma (読点, rtōten, wit. "cwause mark"). In documents dat mix Japanese and Latin scripts, de fuww-widf comma (U+FF0C，FULLWIDTH COMMA) is used; dis is de standard form of comma (t逗號, s逗号, pdòuhào) in China. Since East Asian typography permits commas to join cwauses deawing wif certain topics or wines of dought, commas may separate subjects and predicates and constructions dat wouwd be considered a "comma spwice" in Engwish are acceptabwe and commonwy encountered.

The comma in de Arabic script (used by Arabic, Urdu, and Persian, etc.) is inverted, upside-down: '،' (U+060C،ARABIC COMMA), in order to distinguish it from de Arabic diacriticḍammah (ُ), representing de vowew /u/, which is simiwarwy comma-shaped.[36] In Arabic texts, Western-stywed comma (٫) is used as a decimaw point.

Reversed comma (U+2E41⹁REVERSED COMMA) is used in Sindhi when written in Arabic script. It is different from de standard Arabic comma.

The comma is used as a diacritic mark in Romanian under de s (Ș, ș), and under de t (Ț, ț). A cediwwa is occasionawwy used instead of it, but dis is technicawwy incorrect. The symbow d̦ (d wif comma bewow) was used as part of de Romanian transitionaw awphabet (19f century) to indicate de sounds denoted by de Latin wetter z or wetters dz, where derived from a Cyriwwicѕ (/dz/). The comma and de cediwwa are bof derivative of a smaww cursive z (ʒ) pwaced bewow de wetter. From dis standpoint awone, ș, ț, and d̦ couwd potentiawwy be regarded as stand-ins for sz, tz, and dz respectivewy.

In Latvian, de comma is used on de wetters ģ, ķ, ļ, ņ, and historicawwy awso ŗ, to indicate pawatawization. Because de wowercase wetter g has a descender, de comma is rotated 180° and pwaced over de wetter. Awdough deir Adobegwyph names are commas, deir names in de Unicode Standard are g, k, w, n, and r wif a cediwwa. They were introduced to de Unicode standard before 1992, and deir name cannot be awtered.

In Livonian, whose awphabet is based on a mixture of Latvian and Estonian awphabets, de comma is used on de wetters ḑ, ļ, ņ, ŗ, ț to indicate pawatawization in de same fashion as Latvian, except dat Livonian uses ḑ and ț represent de same pawatawpwosive phonemes which Latvian writes as ģ and ķ respectivewy.

In Czech and Swovak, de diacritic in de characters ď, ť, and ľ resembwes a superscript comma, but it is used instead of a caron because de wetter has an ascender. Oder ascender wetters wif carons, such as wetters ȟ (used in Finnish Romani and Lakota) and ǩ (used in Skowt Sami), did not modify deir carons to superscript commas.

In 16f-century Guatemawa, de archaic wetter cuatriwwo wif a comma (Ꜯ, ꜯ) was used to write Mayan wanguages.[38]

^Huda Smitshuijzen AbiFarès (2001). Arabic Typography: A Comprehensive Sourcebook. London: Saqi Books. p. 106. ISBN978-0-86356-347-8. The comma used in Arabic script is not onwy a mirror image of its Latin counterpart, but its taiw is awso turned upwards in order to avoid any possibiwity of confusing it wif de Dammah, de u short vowew mark.